Yes, performance will be largely the same on 0.4.

If you have to do any performance sensitive code at scale MPI is really the 
only option I can recomend now.  I don't know what you are trying to do but 
the MPI.jl library is a bit incomplete so it would be great if you used it 
and could contribute back in some way.  All the basic operations should be 
covered.

-Jake

On Thursday, April 30, 2015 at 12:29:15 PM UTC-4, Ángel de Vicente wrote:
>
> Hi Jake, 
>
> Jake Bolewski <[email protected] <javascript:>> writes: 
> > DistributedArray performance is pretty bad.  The reason for removing 
> > them from base was to spur their development.  All I can say at this 
> > time is that we are actively working on making their performance 
> > better. 
>
> OK, thanks. Should I try with the DistributedArray package in 0.4-dev or 
> for the moment the performance will be similar? 
>
>
> > For every parallel program you have implicit serial overhead (this is 
> > especially true with multiprocessing).  The fraction of serial work to 
> > parallel work determines your potential parallel speedup.  The 
> > parallel work / serial overhead in this case is really bad, so I don't 
> > think your observation is really surprising.  If this is on a shared 
> > memory machine I would try using SharedArray's as the serial 
> > communication overhead will be lower, and the potential parallel 
> > speedup much higher.  DistributedArrays only really make sense if they 
> > are in fact distributed over multiple machines. 
>
> I will try SharedArray's, but the goal is to be able to run the code 
> (not this one :-)) over distributed machines. For the moment my only 
> hope is MPI.jl then? 
>
> Thanks, 
> -- 
> Ángel de Vicente 
> http://www.iac.es/galeria/angelv/           
>

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